Patent GB-597915-A (GB)
Title: Improvement in methods and apparatus for producing reaction forces for propelling purposes
IPC: F02K7/06
Filed: 1945-08-17
Abstract: 597,915. Generating combustion products under pressure. LINDEROTH, E. T. Aug. 17, 1945, No. 21093. Convention date, June 2, 1944. [Class 51 (i)] [Also in Groups XXVI; XXVII, XXVIII and XXXIII] In a jet-reaction propelling unit of the kind wherein intermittent explosions occur in a ball shaped combustion chamber the inertia of the issuing gas in the ejector tube is used to scavenge the combustion chamber and to suck thereinto a new charge of air and fuel past a non-return inlet valve. The scavenging is made more effective by whirling the new air to lay it centrifugally against the walls of the combustion chamber to press the combustion products towards the exit. The new air can be admitted under the pressure produced in a tube forwardly directed in the line of motion, the length of the tube being such that pulsations are built up therein. As shown in Figs. 7, 8, two combustion chambers 4, 5 are used with one ejector system 6, 7, one chamber being scavenged by the suction produced by the explosion gases issuing from the other chamber. The portion 6 of the ejector leads to a pulsator tube 7 and comprises a number of overlapping nozzles which are mainly cylindrical in internal form or slightly divergent towards the tube 7, and become progressively larger. The nozzles are designed to enclose a space corresponding in shape to the envelope of a jet liberated in free air so that interference with the combustion gases is avoided. The nozzles are designed to minimize losses in meeting the speed wind, vacuum being produced within the spaces between successive nozzles which vacuum adds to the effective thrust of the jet. The fuel supply is effected by diaphragm pumps 26, 27, the pump 26 being operated by the explosion in the chamber 4 to supply fuel to the chamber 5, the pump 27 being operated by the chamber 5. The diaphragm 31, when pushed forward, accelerates the fuel along the pipe 30, a pump action being obtained, in the absence of a valve in the pipe 30, by the inertia effect of the column of fuel in the pipe. The air bell 29 neutralizes the inertia effect of the fuel in the suction pipe. When the diaphragm returns, the fuel column in the pipe 30 is brought to rest and finally moved backwards, so that air is sucked into the nozzles 19. This air must be ejected before the next charge of fuel can be supplied, and this results in the initial fuel supply lagging behind the initial air supply, so that the scavenging tends to be effected by air only. The sparking-plug 40 (see Group XXVIII) reaches to the centre of the combustion chamber and is fired by the valve spindle 15 closing a contact 20 in the ignition circuit. The contact is carried by a spring 21 weaker than the spring 13 on the spindle 15 which spring is itself weak to ensure easy opening of the valve before a stronger short spring 14 arrests it. A light construction of valve is permitted by mounting the closure member on the spindle by means of a ball joint 17 warping being thus obviated. The thinness of the spindle 15 minimises the heat transferred to the spindle guide which may therefore be of synthetic resin. The whirling of the combustion air is effected by vanes 33, or alternatively by a spiral shaped inlet passage. Cooling of the combustion chambers and nozzles is effected by the speed wind via a diffuser 36 and very narrow jackets 35, 38 in which the air attains a high velocity which is accentuated by the vacuum effect at the nozzle ends. In Fig. 12, a unit with a single combustion chamber 5 is. shown with a pulsator tube 44 feeding the inlet valve 12 through a spiral 44a. The tube. 44 resonates with the tube 7 whereby a slight compression of charge is effected in the chamber 5. The air intake 51 is shaped to obtain the maximum compression from the speed wind. The engine is started by a spring-operated air pump 49. The handle is pulled back, the spring is locked by a pawl which is released to blow air into the tube 44. A wire spiral, 45, Fig. 14, which is centrally disposed in the chamber and is kept glowing by the heat of combustion, effects the ignition, but, for starting sparking plug 46 is provided which may be fired by a contact on the valve spindle as described above. The fuel injection is effected by the pulsation in the tube 44. When pressure exists in the tube 44 air is forced into the annular part 48 of the nozzle, and this air must be ejected when the fuel column in the pipe 30 moved forward because of vacuum in the tube 44. The kinetic energy of the fuel column is sufficient to maintain fuel injection during the greater part of the pressure period. The amount of air admitted to the nozzle part 48 is controlled by adjusting the travel of a ball valve 28 by a screw 47, and adjustment of a valve 32 ensures that fuel injection is stopped before the valve 12 shuts. In a modification (see Group XXXIII) the axes of the combustion chamber, inlet valve nozzle, ejector and pulsator tube are aligned, ignition being effected by the hot nozzle extending into the combustion chamber. Specification 124,736, [Class 110 (iii)], is referred to.